Experimental observation of the M1 scissors mode in 254No

F. L. Bello Garrote; A. Lopez-Martens; A. C. Larsen; I. Deloncle; S. Péru; F. Zeiser; P. T. Greenlees; B. V. Kheswa; K. Auranen; D. L. Bleuel; D. M. Cox; L. Crespo Campo; F. Giacoppo; A. Görgen; T. Grahn; M. Guttormsen; T. W. Hagen; L. Harkness-Brennan; K. Hauschild; G. Henning; R. D. Herzberg; R. Julin; S. Juutinen; T. A. Laplace; M. Leino; J. E. Midtbø; V. Modamio; J. Pakarinen; P. Papadakis; J. Partanen; T. Renstrøm; K. Rezynkina; M. Sandzelius; J. Sarén; C. Scholey; S. Siem; J. Sorri; S. Stolze; J. Uusitalo

doi:10.1016/j.physletb.2022.137479

Experimental observation of the M1 scissors mode in ²⁵⁴No

F. L. Bello Garrote, A. Lopez-Martens, A. C. Larsen, I. Deloncle, S. Péru, F. Zeiser, P. T. Greenlees, B. V. Kheswa, K. Auranen, D. L. Bleuel, D. M. Cox, L. Crespo Campo, F. Giacoppo, A. Görgen, T. Grahn, M. Guttormsen, T. W. Hagen, L. Harkness-Brennan, K. Hauschild, G. HenningR. D. Herzberg, R. Julin, S. Juutinen, T. A. Laplace, M. Leino, J. E. Midtbø, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, T. Renstrøm, K. Rezynkina, M. Sandzelius, J. Sarén, C. Scholey, S. Siem, J. Sorri, S. Stolze, J. Uusitalo

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

We present the first experimental evidence of the scissors mode in the superheavy nucleus ²⁵⁴No produced in the ²⁰⁸Pb(⁴⁸Ca, 2nγ))²⁵⁴No reaction. The spectrum of γ rays emitted by the excited ²⁵⁴No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of ²⁵⁴No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μ_N². This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.

Original language	English
Article number	137479
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	834
DOIs	https://doi.org/10.1016/j.physletb.2022.137479
Publication status	Published - 10 Nov 2022
Externally published	Yes

Keywords

Scissors mode
Transfermium nuclides
γ-strength function

ASJC Scopus subject areas

Nuclear and High Energy Physics

Access to Document

10.1016/j.physletb.2022.137479

Cite this

Bello Garrote, F. L., Lopez-Martens, A., Larsen, A. C., Deloncle, I., Péru, S., Zeiser, F., Greenlees, P. T., Kheswa, B. V., Auranen, K., Bleuel, D. L., Cox, D. M., Crespo Campo, L., Giacoppo, F., Görgen, A., Grahn, T., Guttormsen, M., Hagen, T. W., Harkness-Brennan, L., Hauschild, K., ... Uusitalo, J. (2022). Experimental observation of the M1 scissors mode in ²⁵⁴No. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 834, Article 137479. https://doi.org/10.1016/j.physletb.2022.137479

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title = "Experimental observation of the M1 scissors mode in 254No",

abstract = "We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2nγ))254No reaction. The spectrum of γ rays emitted by the excited 254No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.",

keywords = "Scissors mode, Transfermium nuclides, γ-strength function",

author = "{Bello Garrote}, {F. L.} and A. Lopez-Martens and Larsen, {A. C.} and I. Deloncle and S. P{\'e}ru and F. Zeiser and Greenlees, {P. T.} and Kheswa, {B. V.} and K. Auranen and Bleuel, {D. L.} and Cox, {D. M.} and {Crespo Campo}, L. and F. Giacoppo and A. G{\"o}rgen and T. Grahn and M. Guttormsen and Hagen, {T. W.} and L. Harkness-Brennan and K. Hauschild and G. Henning and Herzberg, {R. D.} and R. Julin and S. Juutinen and Laplace, {T. A.} and M. Leino and Midtb{\o}, {J. E.} and V. Modamio and J. Pakarinen and P. Papadakis and J. Partanen and T. Renstr{\o}m and K. Rezynkina and M. Sandzelius and J. Sar{\'e}n and C. Scholey and S. Siem and J. Sorri and S. Stolze and J. Uusitalo",

note = "Publisher Copyright: {\textcopyright} 2022 The Author(s)",

year = "2022",

month = nov,

day = "10",

doi = "10.1016/j.physletb.2022.137479",

language = "English",

volume = "834",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier",

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Bello Garrote, FL, Lopez-Martens, A, Larsen, AC, Deloncle, I, Péru, S, Zeiser, F, Greenlees, PT, Kheswa, BV, Auranen, K, Bleuel, DL, Cox, DM, Crespo Campo, L, Giacoppo, F, Görgen, A, Grahn, T, Guttormsen, M, Hagen, TW, Harkness-Brennan, L, Hauschild, K, Henning, G, Herzberg, RD, Julin, R, Juutinen, S, Laplace, TA, Leino, M, Midtbø, JE, Modamio, V, Pakarinen, J, Papadakis, P, Partanen, J, Renstrøm, T, Rezynkina, K, Sandzelius, M, Sarén, J, Scholey, C, Siem, S, Sorri, J, Stolze, S & Uusitalo, J 2022, 'Experimental observation of the M1 scissors mode in ²⁵⁴No', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 834, 137479. https://doi.org/10.1016/j.physletb.2022.137479

TY - JOUR

T1 - Experimental observation of the M1 scissors mode in 254No

AU - Bello Garrote, F. L.

AU - Lopez-Martens, A.

AU - Larsen, A. C.

AU - Deloncle, I.

AU - Péru, S.

AU - Zeiser, F.

AU - Greenlees, P. T.

AU - Kheswa, B. V.

AU - Auranen, K.

AU - Bleuel, D. L.

AU - Cox, D. M.

AU - Crespo Campo, L.

AU - Giacoppo, F.

AU - Görgen, A.

AU - Grahn, T.

AU - Guttormsen, M.

AU - Hagen, T. W.

AU - Harkness-Brennan, L.

AU - Hauschild, K.

AU - Henning, G.

AU - Herzberg, R. D.

AU - Julin, R.

AU - Juutinen, S.

AU - Laplace, T. A.

AU - Leino, M.

AU - Midtbø, J. E.

AU - Modamio, V.

AU - Pakarinen, J.

AU - Papadakis, P.

AU - Partanen, J.

AU - Renstrøm, T.

AU - Rezynkina, K.

AU - Sandzelius, M.

AU - Sarén, J.

AU - Scholey, C.

AU - Siem, S.

AU - Sorri, J.

AU - Stolze, S.

AU - Uusitalo, J.

PY - 2022/11/10

Y1 - 2022/11/10

N2 - We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2nγ))254No reaction. The spectrum of γ rays emitted by the excited 254No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.

AB - We present the first experimental evidence of the scissors mode in the superheavy nucleus 254No produced in the 208Pb(48Ca, 2nγ))254No reaction. The spectrum of γ rays emitted by the excited 254No nuclei shows an enhanced γ-ray yield for transition energies of ≈2.5 MeV. By measuring the linear polarization properties of the emitted γ rays, we confirm that the transitions in the enhancement region are predominantly of magnetic-dipole character, characteristic for the scissors mode. To further characterize the enhanced γ-ray yield, simulations of the electromagnetic decay of 254No were performed. The observed enhancement is reproduced by including an M1 component in the γ strength function with total strength B(M1↑)=11.8(19)μN2. This is in good agreement with the integrated M1 strength from sum-rule estimates and new calculations within the quasi-particle random-phase approximation presented here. Our results provide a stringent test of phenomenological formulae for the scissors mode currently used in stellar nucleosynthesis calculations. We find that those formulae are not satisfactory, and we recommend using sum-rule estimates assuming a rigid-body moment of inertia instead for describing the scissors mode in superheavy nuclei.

KW - Scissors mode

KW - Transfermium nuclides

KW - γ-strength function

UR - http://www.scopus.com/inward/record.url?scp=85139292106&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2022.137479

DO - 10.1016/j.physletb.2022.137479

M3 - Article

AN - SCOPUS:85139292106

SN - 0370-2693

VL - 834

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 137479

ER -